Note 448 — Chapter XV

These celebrated ships are built of iron. The length between the perpendiculars is 334 feet; the beam is 35 feet, and depth 21 feet. There is a centre keel plate, 3 feet deep and ⅝ inch thick, with two bars, 9 inches deep by ⅝ inch thick, on each side at the bottom forming also the keelson; the plate, with the two garboard strakes, ⅞ inch thick each, are secured together with iron bolts riveted and countersunk. On the top of the centre keel plate, two angle-iron bars are riveted, 5 inches by 4 inches by ½ inch, and to these angle irons, and to the angle irons on the top of the floorings throughout the entire length of the vessel, as far as the fine ends will allow, is riveted a strong plate, 4 feet wide amidships, and 2 feet 6 inches wide at the ends. There are, also, two very strong box keelsons, secured on the floorings at each side of the keel, and another in each bilge. The engine bed-plates, paddle and spring beams, and all other beams for the main and lower decks, are of iron. Timber has been used only for the decks and cabin fittings. There are nine principal iron water-tight bulkheads, which not only provide for the safety of the ship in case of accident, but add greatly to her strength in a seaway. The bulwarks are of iron plates, in continuation of the sides of the vessel to the rail, and without any break for gangways, such not being required for landing either at Holyhead or at Kingstown. To give additional strength in the centre of the vessel, where the weight of the engines, wheels, and boilers has to be carried, the insides of the paddle-boxes are also formed of iron plates, continued from the sides and bulwarks of the vessel, with a strong bow girder, formed of an iron plate 15 inches broad and ¾ inch thick, so as to provide ample means of resistance to the severe shocks which these long vessels must encounter in rough seas, when driven at their high rate of speed. The gunwale is formed of angle-iron bars, 4 inches by 4 inches, riveted to the sheer strake and to a plate which is riveted on the top of the beams. At a distance of about 15 inches from this, an inner angle bar is riveted, against which the wooden waterway is fitted, so as to leave the outer part, between this and the gunwale, to form a drain to take the water off the deck, and to discharge it through the scuppers. This arrangement, which was introduced by the late Mr. John Laird, has been found very convenient in freeing the decks quickly from water. These iron gunwale plates are 5 feet wide by ¾ inch thick amidships, tapering gradually to about 2 feet 6 inches by ½ inch at the ends, with a system of diagonal tie plating from side to side, securely bolted or riveted to the deck beams. Between the paddle-boxes an upper deck, about 50 feet in length, has been placed.